Create the /etc/mtab file if does not exists

[rhatdan]

We should create the /etc/mtab->/proc/mountinfo link
so that mount command will work within the container.

Docker does this by default.

Fixes: #10263

Signed-off-by: Daniel J Walsh [email protected]

[openshift-ci-robot]

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[TomSweeneyRedHat]

All kinds of red unhappy tests @rhatdan

[mheon]

Can we do this with a bind mount of the link? As is, we’re creating a file that will show up in diff, be committed with user changes, etc

…

On Fri, May 7, 2021 at 17:07 Tom Sweeney ***@***.***> wrote: All kinds of red unhappy tests @rhatdan <https://github.com/rhatdan> — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#10270 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AB3AOCHXF3FXI4HOOIIWYNLTMRJANANCNFSM44K4KRSA> .

[giuseppe]

LGTM

[rhatdan]

@mheon We already do this, with /etc/resolv.conf and /etc/hosts, if they do not exist in the base image. We could create an empty file for the inode and mount over it, but I am not sure this is better then setting up the image with the symbolic link, which BTW almost all images have by default, which is why we never caught this until now. We can talk at standup about potentially special handling the additional mount inodes we add to images.

[mheon]

We bind-mount hosts, resolv, and most others (with a few notable exceptions) - it seems more sane than creating files in the container’s own RW layer unless there is a good reason not to

…

On Mon, May 10, 2021 at 06:28 Daniel J Walsh ***@***.***> wrote: @mheon <https://github.com/mheon> We already do this, with /etc/resolv.conf and /etc/hosts, if they do not exist in the base image. We could create an empty file for the inode and mount over it, but I am not sure this is better then setting up the image with the symbolic link, which BTW almost all images have by default, which is why we never caught this until now. We can talk at standup about potentially special handling the additional mount inodes we add to images. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#10270 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AB3AOCHAOCIYW4NUPD63SVLTM6YNXANCNFSM44K4KRSA> .

[giuseppe]

just a nit that could be addressed later,

LGTM

[giuseppe]

could this be simplified as?

if err = os.Symlink("/proc/mounts", mtab); err != nil && !os.IsExist(err) {
	return "", err
}

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: giuseppe, rhatdan

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[TomSweeneyRedHat]

LGTM
but I'll let @mheon hit the merge button based on his last comment.